Big Picture Science – The Light Stuff

by Gary Niederhoff on August 23, 2015

thelightstuffBIGGER
Big Picture Science – The Light Stuff

The light bulb needs changing. Edison’s incandescent bulb, virtually unaltered for more than a century, is now being eclipsed by the LED. The creative applications for these small and efficient devices are endless: on tape, on wallpaper, even in contact lenses. They will set the world aglow. But is a brighter world a better one?

Discover the many ingenious applications for LEDs and the brilliance of the 19th century scientist, James Clerk Maxwell, who first discovered just what light is. But both biologists and astronomers are alarmed by the disappearance of dark. Find out how light pollution is making us and other animals sick and – when was the last time you saw a starry night?

Listen to individual segments here:
Part 1: Ian Ferguson / LEDs
Part 2: Jay Neitz / Color Vision
Part 3: Martin Hendry / James Clerk Maxwell
Part 4: John Barentine / Dark Skies

{ 3 comments… read them below or add one }

avatar Davia August 25, 2015 at 10:10 pm

I enjoy the idea of more natural daytime changing light colors. Maybe someday the science behind bio-luminescence will solve a lot of our light issues even though right now it’s not so great.

avatar Steve Bergman February 28, 2016 at 10:56 am

There are all sorts of problems with the first segment of this episode. Standard line voltage in the US is now 125V. Not 110V. Just because LEDs operate on low voltage doesn’t mean that 125V AC is going away. We’re certainly not going to be running our microwave ovens and hair dryers on 3V DC. I’ve been using compact fluorescent bulbs exclusively since before they were even called that (and were not particularly compact) in the late 70s and early 80s. They have never had a “bluish” tinge. Not unless you buy the daylight spectrum bulbs which are between 5000K and 6500K color temp. The standard soft white (2700K) bulbs are not at all blue. If anything, they are slightly yellower than incandescent. If this bothers you, use bright white bulbs, which are more like 3000K. Current CFL’s are dirt cheap, more compact than incansescent bulbs, last 10,000 to 120,000 hours, and contain only 1 – 4 mg mercury. Even if you don’t recycle, they result in a net decrease in mercury in the environment since 60% of the US’s energy comes from coal plants, which emit mercury right into the atmosphere. There electricity savings of the CFL far more than makes up for the tiny dot of Hg they contain.

It should also be noted that it has been decades since CFLs “flickered”. Modern bulbs operating not at 60Hz, but in the MHz range. And since the phosphorescent coatings have a lag to time to respond, there is no flicker at all. Not even a really fast one.

In short. CFLs are one of the most badly and erroneously maligned technologies in history. And I blame people’s ignorance and lack of critical thinking skills for that.

That said, current LED’s are even more impressive in some ways, and I moved to them a couple of years ago. Current 100w equivalents (producing 1600+ lumens) can be had from the hardware store for around $30 now. And while a bit heavy, they really are not “unweildly”. They last even longer than CFLs. Most are rated for at leasr 25,000 hours. And most are probably actually good for ~100,000.hours. My 1680 lumen bulbs draw less than 20W, giving them an efficiency of greater that 84 lumens/watt. IIRC, 150W 3-way equivalents still run ~$49 a piece. Depending upon one’s finances, CFL might still make the most sense there. I suspect that this will change within a year’s time.

avatar Steve Bergman February 28, 2016 at 11:23 am

That 10,000 hr to 120,000 hr claim is a typo. Should read 10,000 to 12,000 hours. Also, I should mention that modern CFLs and LEDs have about the same color rendering indeces. Typically 80 – 82 CRI. Color Rendering Index is a measure of how accurately they render the color of objects lit by them..

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